[Visual Refresh] Revert floating border usage back to using pseudo elements#9080

mgadewoll merged 9 commits intoelastic:eui-theme/borealis-v2-pocelastic/eui:eui-theme/borealis-v2-pocfrom

mgadewoll:theme/shadows-with-pseudo-element-bordermgadewoll/eui:theme/shadows-with-pseudo-element-borderCopy head branch name to clipboard